From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f181.google.com (mail-wi0-f181.google.com [209.85.212.181]) by dpdk.org (Postfix) with ESMTP id DAF6A6896 for ; Wed, 24 Sep 2014 17:12:04 +0200 (CEST) Received: by mail-wi0-f181.google.com with SMTP id z2so7514940wiv.8 for ; Wed, 24 Sep 2014 08:18:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:organization :user-agent:in-reply-to:references:mime-version :content-transfer-encoding:content-type; bh=ylZSqgr6HPPpj6ouNtb0BrG2Nb5jcct/iZhA0md9BvI=; b=XX4lzPNzD1mS7oSzHjfgb7tUHzvF2Fw6moXeNz9yqoFlWuaC7Ml0NslmOOwC0YmqT+ FVt8eqX4Y6SDkwAXpaGP+CSlyUiCr8t7N+tw1fwrWevqqfQmh0pq81REILBmfVItrjQ5 wDxm1+LXUJYA920nKrVh3dh8vG+l6pQZ4A6pgEyoUHHRZWNQQy2epKxLqbpvXIAu7BhK fxEiO8SgVpkcYD0tD0O0xuwcfvrwaRkA0iqUX04Y72B0OvZBPH5STkvzSB/ZJGGxEOJu m4hfbxUlI6fVAA3czZgwW7j6ij5t/LD9udsEimcvSEwRlZnjrprxwWRuJ0mYx+z5zlsQ PWQA== X-Gm-Message-State: ALoCoQlf7HXrKxV3O+QobFkAcANdRFgrFGzxUENcev4t9Ms6EZFLI96kWDVa21GyXpNsnPsdaX8K X-Received: by 10.180.83.195 with SMTP id s3mr32728934wiy.12.1411571897907; Wed, 24 Sep 2014 08:18:17 -0700 (PDT) Received: from xps13.localnet (136-92-190-109.dsl.ovh.fr. [109.190.92.136]) by mx.google.com with ESMTPSA id ec18sm57685wic.0.2014.09.24.08.18.16 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Sep 2014 08:18:17 -0700 (PDT) From: Thomas Monjalon To: dev@dpdk.org, Hiroshi Shimamoto Date: Wed, 24 Sep 2014 17:18:09 +0200 Message-ID: <1855491.X6obi8qxOV@xps13> Organization: 6WIND User-Agent: KMail/4.13.3 (Linux/3.15.8-1-ARCH; KDE/4.13.3; x86_64; ; ) In-Reply-To: <7F861DC0615E0C47A872E6F3C5FCDDBD011A9934@BPXM14GP.gisp.nec.co.jp> References: <7F861DC0615E0C47A872E6F3C5FCDDBD011A9934@BPXM14GP.gisp.nec.co.jp> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Cc: Hayato Momma Subject: Re: [dpdk-dev] [memnic PATCH 4/7] pmd: use compiler barrier X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Sep 2014 15:12:05 -0000 2014-09-11 07:48, Hiroshi Shimamoto: > x86 can keep store ordering with standard operations. Are we sure it's always the case (including old 32-bit CPU)? I would prefer to have a reference here. I know we already discussed this kind of things but having a reference in commit log could help for future discussions. > Using memory barrier is much expensive in main packet processing loop. > Removing this improves xmit/recv packet performance. > > We can see performance improvements with memnic-tester. > Using Xeon E5-2697 v2 @ 2.70GHz, 4 vCPU. > size | before | after > 64 | 4.18Mpps | 4.59Mpps > 128 | 3.85Mpps | 4.87Mpps > 256 | 4.01Mpps | 4.72Mpps > 512 | 3.52Mpps | 4.41Mpps > 1024 | 3.18Mpps | 3.64Mpps > 1280 | 2.86Mpps | 3.15Mpps > 1518 | 2.59Mpps | 2.87Mpps > > Note: we have to take care if we use temporal cache. Please, could you explain this last sentence? Thanks -- Thomas